// EXCLUDE_FROM_GALLERY_DOCS_END
import 'package:charts_flutter/flutter.dart' as charts;
import 'package:flutter/material.dart';
import 'dart:math';
import 'package:charts_flutter/flutter.dart';
import 'package:charts_flutter/src/text_element.dart' as textElement;
import 'package:charts_flutter/src/text_style.dart' as style;

class SelectionLineHighlight extends StatelessWidget {
  final List<charts.Series> seriesList;
  final bool animate;
  static String _selectSales;

  SelectionLineHighlight(this.seriesList, {this.animate});

  /// Creates a [LineChart] with sample data and no transition.
  factory SelectionLineHighlight.withSampleData() {
    return new SelectionLineHighlight(
      _createSampleData(),
      // Disable animations for image tests.
      animate: false,
    );
  }

  @override
  Widget build(BuildContext context) {
    var _onSelectionChanged = (charts.SelectionModel selectionModel) {
      final selectedDatum = selectionModel.selectedDatum;
      if (selectedDatum.isNotEmpty) {
        selectedDatum.forEach((charts.SeriesDatum datumPair) {
          print(datumPair.datum.sales);
          _selectSales = datumPair.datum.sales.toString();
        });
      }
    };

    // This is just a simple line chart with a behavior that highlights the
    // selected points along the lines. A point will be drawn at the selected
    // datum's x,y coordinate, and a vertical follow line will be drawn through
    // it.
    //
    // A [Charts.LinePointHighlighter] behavior is added manually to enable the
    // highlighting effect.
    //
    // As an alternative, [defaultInteractions] can be set to true to include
    // the default chart interactions, including a LinePointHighlighter.
    return new charts.LineChart(seriesList, animate: animate, behaviors: [
      // Optional - Configures a [LinePointHighlighter] behavior with a
      // vertical follow line. A vertical follow line is included by
      // default, but is shown here as an example configuration.
      //
      // By default, the line has default dash pattern of [1,3]. This can be
      // set by providing a [dashPattern] or it can be turned off by passing in
      // an empty list. An empty list is necessary because passing in a null
      // value will be treated the same as not passing in a value at all.
      new charts.LinePointHighlighter(
          showHorizontalFollowLine:
              charts.LinePointHighlighterFollowLineType.none,
          showVerticalFollowLine:
              charts.LinePointHighlighterFollowLineType.nearest,
          symbolRenderer: CustomCircleSymbolRenderer(),
      ),
      new charts.SeriesLegend(),
      // Optional - By default, select nearest is configured to trigger
      // with tap so that a user can have pan/zoom behavior and line point
      // highlighter. Changing the trigger to tap and drag allows the
      // highlighter to follow the dragging gesture but it is not
      // recommended to be used when pan/zoom behavior is enabled.
      new charts.SelectNearest(eventTrigger: charts.SelectionTrigger.tapAndDrag)
    ],
    selectionModels: [
      new charts.SelectionModelConfig(
        type: charts.SelectionModelType.info,
        changedListener: _onSelectionChanged,
      ),
    ]);
  }

  /// Create one series with sample hard coded data.
  static List<charts.Series<LinearSales, int>> _createSampleData() {
    final data = [
      new LinearSales(0, 5),
      new LinearSales(1, 25),
      new LinearSales(2, 100),
      new LinearSales(3, 75),
    ];

    return [
      new charts.Series<LinearSales, int>(
        id: 'Sales',
        domainFn: (LinearSales sales, _) => sales.year,
        measureFn: (LinearSales sales, _) => sales.sales,
        data: data,
      )
    ];
  }
}

/// Sample linear data type.
class LinearSales {
  final int year;
  final int sales;

  LinearSales(this.year, this.sales);
}

class CustomCircleSymbolRenderer extends CircleSymbolRenderer {
  CustomCircleSymbolRenderer({bool isSolid=false}): super(isSolid: isSolid);

  @override
  void paint(ChartCanvas canvas, Rectangle<num> bounds,
      {List<int> dashPattern,
      Color fillColor,
      FillPatternType fillPattern,
      Color strokeColor,
      double strokeWidthPx}) {
    super.paint(canvas, bounds, dashPattern: dashPattern, fillColor: fillColor, strokeColor: strokeColor, strokeWidthPx: strokeWidthPx);
    // canvas.drawRect(
    //   Rectangle(bounds.left - 5, bounds.top - 30, bounds.width + 10, bounds.height + 10),
    //   fill: Color.white
    // );
    var textStyle = style.TextStyle();
    textStyle.color = fillColor;
    textStyle.fontSize = 15;
    textStyle.fontFamily = 'Bold';
    
    canvas.drawText(
      textElement.TextElement(SelectionLineHighlight._selectSales, style: textStyle),
        (bounds.left + bounds.width * 2).round(),
        (bounds.top).round()
    );
  }
}

class SelectionLabel with ChangeNotifier {
  String _label;
  get label => _label;

  void labelChanged(String label) {
    this._label = label;
    notifyListeners();
  }
}
